Ecology Letters

Virtual Issues

The Structure and Effects of Biodiversity from Oceans to Mountains

Compiled by Marcel Holyoak, Editor-in-Chief

The 2014 Ecological Society of America annual meeting in Sacramento, California has a theme of “From Oceans to Mountains: It’s All Ecology,” emphasizing the striking gradients and geographical patterns of both the physical environment and biodiversity of the State. The meeting also aims to learn from the past in order to shape the future conservation and management of biodiversity. In line with this aim this Virtual Issue highlights articles from Ecology Letters within the last 5 years. Three broad types of articles are represented.

The first four articles are about major structure of biodiversity, either from the perspective of studying such structure. Four articles then address either the measurement or ecological effects of phylogenetic structure.

The Virtual Issue then turns to anthropogenic effects on biodiversity. Articles impacts of climate change, differential impacts on taxonomic, phylogenetic and functional diversity, effects of landscape heterogeneity and organic farming in agricultural landscapes, impacts of invasive species on biodiversity, the long-term effects of nutrient enrichment in terrestrial systems, and finally effects of removal of top predators in marine systems . Collectively we hope these articles provoke creative thinking about the structure and conservation of biodiversity in systems as diverse as oceans, microbial community and terrestrial plant communities.

Early naturalists such as Darwin were fascinated by both the diversity and complexity of nature. Today we understand that biodiversity encompasses an enormous variety of levels, from taxonomic, to phylogenetic, functional and cultural. Over the last several decades we have increasingly started to come to terms with the importance of these various levels for understanding the functioning of ecosystems and the relationship to ecosystem services. As we have entered what conservation biologists have termed the Anthropocene, an era of human domination of our planet, we have developed practical and reactive disciplines such as conservation biology, invasion biology, urban ecology, bioeconomics, and human ecology. The challenges have become even greater since our recognition of the impending reality of global climate change. In compiling this issue to mark The Year of Biodiversity we have selected articles that discuss the future of biodiversity, how we can assess biodiversity given imperfect knowledge, connections with anthropogenic impacts and ecosystem functioning. We end with a challenging question, with an economic look at the consequences of delaying conservation action until we have better information versus acting more immediately.

As human populations continue to grow it becomes increasingly important to understand human effects on biodiversity and the functioning of ecosystems. This (the theme of this Virtual Issue) coincides with the 97th annual meeting of the Ecological Society of America, “Life on Earth: Preserving, Utilizing, and Sustaining our Ecosystems.” The selected articles are intended to provoke thought about how to tackle a theme that challenges us all, as well as to promote a broader understanding of the problems involved. Our theme spans levels of biological organization from genes (Hughes et al. 2008) to ecosystems, and necessitates considering landscapes that incorporate multiple ecosystem types. An obvious challenge is to understand the responses of biodiversity to anthropogenic change (Knapp et al. 2008; Hahs et al. 2009, Graham et al. 2011). This difficulty is amplified again when we turn to ecosystems. Ecosystems represent complex systems where it is hard to identify relevant levels of biological organization (e.g., Hillebrand and Matthiessen 2009) and to understand how change in one factor leads to change in others (e.g., Bennett et al. 2009, Shears and Ross 2010, Compton et al. 2011, McMahon et al. 2012). Part of this complexity comes about because of the complexity of species interactions, and understanding the responses of interacting species to environmental change represent active areas of research (Tylianakis et al. 2008; Hunsicker et al. 2011; Ferrari et al. 2011). Landscape context is inescapable and it is increasingly realized that both biodiversity and ecosystem functioning are modified by connectivity and landscape composition (Lindenmayer et al. 2008, Staddon et al. 2010, Fahrig et al. 2011, Garibaldi et al. 2011). We hope that these articles provoke creative thinking and further research that will help us create and preserve diverse and functioning ecological systems.

This special issue marks The UN International Year of Forests by bringing together articles about forest conservation, climate change, and how species traits relate to emergent patterns and processes.

A timely synthesis of how current human and ecological processes jointly drive spatial and temporal biodiversity patterns in tropical forests is provided by Gardner et al. (2009). These authors develop an adaptive-landscape planning framework to aid us in understanding the role of humans in forest degradation and in identifying key areas of uncertainty. Conservation and management are inseparable from understanding the mechanisms of forest dynamics. Gap dynamics are an important theme in forest dynamics. For instance, Norden et al. (2009) show how the resilient convergence of secondary forest with primary forest depends on the abundance and connectivity of species within habitat fragments within a region.

Understanding the effects of climate change and global change are major challenges. Murphy et al. (2010) and Nathan et al. (2011) explore factors explaining how climate change will influence future dispersal and distribution of temperate tree species. Three selected articles investigate effects of climate change on forest composition and ecosystem properties. Schnitzer and Bongers (2011) demonstrate large-scale increases in the abundance and biomass of lianas in lowland tropical and subtropical forests, and Schnitzer and Bongers (2010) show that lianas hinder regeneration of trees in treefall gaps. Drake et al. (2011) exemplify some of the important consequences of climate change for ecosystem functioning. They show dual effects of experimental CO2 enrichment on tree growth and decomposition processes, producing complex interactions between the C and N cycles, with important consequences for carbon sequestration.

An increasing theme in forest ecology is to understand the linkages between species traits, community assembly and diversity. Messier et al. (2010) make the case for the need for a trait-based ecology to understand how biodiversity varies across spatial scales. Other works seek to link traits and species’ life-history or physiology, which might eventually provide mechanisms for scaling biodiversity and/or ecosystem functioning. Three final papers on this theme relate leaf, wood and stem mechanical and physiological properties to ecosystem functioning in forests (Blonder et al. 2011), vegetation types (Baraloto et al. 2010; Chave et al. 2009) and demography more generally (Chave et al. 2009).

Early naturalists such as Darwin were fascinated by both the diversity and complexity of nature. Today we understand that biodiversity encompasses an enormous variety of levels, from taxonomic, to phylogenetic, functional and cultural. Over the last several decades we have increasingly started to come to terms with the importance of these various levels for understanding the functioning of ecosystems and the relationship to ecosystem services. As we have entered what conservation biologists have termed the Anthropocene, an era of human domination of our planet, we have developed practical and reactive disciplines such as conservation biology, invasion biology, urban ecology, bioeconomics, and human ecology. The challenges have become even greater since our recognition of the impending reality of global climate change. In compiling this issue to mark The Year of Biodiversity we have selected articles that discuss the future of biodiversity, how we can assess biodiversity given imperfect knowledge, connections with anthropogenic impacts and ecosystem functioning. We end with a challenging question, with an economic look at the consequences of delaying conservation action until we have better information versus acting more immediately.